The former Huddersfield and Castleford forward, 23, whose twin brother Adam is still with the Robins, has joined the Centurions with immediate effect on a contract until the end of 2015.

Leigh are currently 12 points ahead of second placed Featherstone after 18 games played.

The Bradford-born player made 48 Super League appearances and represented Scotland in 2012 but had to pull out of their 2013 World Cup squad due to a knee injury.

Leigh coach Paul Rowley said: "When we heard that Jonny had become available we quickly did some research and all we got back was positive.

"Jonny was someone I was aware of and to get someone of his ability and potential is a massive signing for our club going forward. I am looking forward to working with him and am sure he will quickly settle in at Leigh and enjoy his time here."